Seasonal variation in the cyanogenetic glucoside content of white clover (Trifolium repens)

Abstract

The importance of cyanogenetic glucosides in plants is dependent on the fact that when the plants are ingested the glucoside is hydrolysed, either by an appropriate enzyme or by ruminal microflora with the release of free HCN which when absorbed in sufficient quantity may be toxic to the grazing animal. Plants which are cyanogenetic occur in a number of genera of the plant kingdom but the toxicity of such plants is a function of a number of factors which involve the animal as well as the plant. A general survey of the literature on the factors involved in HCN content of plants is presented. Literature pertaining to stock poisoning by pure cyanides, cyonogenetic glucosides and cyanogenetic glucosides in plant material is also reviewed. Studies on the seasonal variation in the glucoside content of white clover, made on four single plants of different glucoside content, are described. The results of a similar study with twelve genetically identical plants, are also presented. Results of investigations into HCN content of the different organs of the white clover plant are also reported.